1. Field of the Invention
The present invention generally concerns computer workstations presenting computer-driven video displays, including video displays of graphics information. The present invention more particularly concerns a computer graphics workstation operating under a windowing software system wherein another computer is simultaneously interfaced to the input peripherals and to the output video monitor of the workstation.
2. Background of the Invention--Existing Software and Hardware Components Are Used Within the System of the Invention
The preferred embodiment of the system of the invention will be seen to preferably employ various existing software and hardware components, occasionally with modifications.
A first and a second such existing components used within the preferred embodiment of the invention are two existing computers and their accompanying software systems. The first computer component is preferably a VAXstation II (or other VAXstation family member) available from Digital Equipment Corporation (DEC). The VAXstation.RTM. computer workstation (registered trademark of DEC) typically includes a monitor (normally type VR 290), a keyboard (normally type LK 201) and a locator device (normally a mouse). The VAXstation hardware suite runs a software imaging system program, normally either the VMS.RTM. or the ULTRIX.RTM. (registered trademarks of Digital Equipment Corporation) windowing system programs available from DEC. The combination DEC.RTM.(registered trademark of Digital Equipment Corporation) hardware and software suite permits the generation and display of sophisticated graphics in the performance of generalized computer aided design/ computer aided manufacturing (CAD/CAM) operations.
A second standard computer component preferably used in the system of the present invention is a computer of the IBM Corporation, such as a mainframe computer of the type System 360.TM.or System 370.TM.(trademarks of IBM Corporation). The IBM.RTM. (registered trademark of IBM Corporation) mainframe computer typically runs CAD/CAM software applications programs such as CADAM.RTM. (registered trademark of CADAM, Inc.) or CATIA.RTM. (registered trademark of Dassault Systemes). These mainframe computers and accompanying software programs support graphic displays at graphics terminals, such as at terminal type 5080 available from IBM Corporation, in the performance of CAD/CAM tasks. It will not be necessary in the system of the present invention that the second computer--normally the IBM System 360 or System 370 mainframe--should be running CAD/CAM application software. More mundane software programs such as those performing word processing and other business-related tasks are fully suitable. Any program providing a display will be seen to communicate with a video monitor that is also communicating with the first computer by action of the system of the present invention. The situation wherein an existing VAXstation and an existing IBM mainframe computer are both typically running CAD/CAM applications software merely represents one normal and preferred application of the system of the present invention.
A third existing component used within the system of the present invention is the DesignSet.TM. Communications Controller (DSCC) of Spectragraphics Corporation, San Diego, Calif. (trademark holder and assignee of the present invention). The DSCC is a multi-processor communication controller that attaches directly to a parallel interface host channel of an IBM, or IBM compatible, mainframe computer. This channel connection permits high speed communication with graphics devices that are further connected to the DSCC. The DSCC minimum configuration includes a Channel Processor (CP), a System Processor (SP) and one Communications Processor (CMP). The CP can emulate 128 virtual control units of the graphic and alphanumeric types concurrently, thereby eliminating overhead otherwise incurred by the mainframe processor in managing shared physical control units. The SP performs management of the initial program load, servicing of display station requests for files from system diskette or disk memory, and diagnostic functions. The CMP supports 16 graphics addresses and 16 addresses for terminals type 3270 (of IBM Corporation). Additional CMP's can be added as dictated by the number of terminal devices in the network. The DSCC may optionally be connected to communications adaptors (CA) of Spectragraphics Corporation for protocol conversion resulting in efficient communication, including via local area networks (LAN's), to remote graphics systems.
For the purposes of the present invention, it should be understood that the existing DSCC (and the DS 1082GXP Display Controller to which it is connected, next discussed) buffer information from a mainframe computer. This information later results in a video display. This buffering effectively permits a decoupling of the signals driving a video monitor, and also of the resulting displays on the video monitor, from any required synchronization with the communication channels of the mainframe computers to which the DSCC and Display Controller connect.
A fourth device used, in a modified form, in the system of the present invention is the Display Controller component of the DesignSet.TM. 1082GXP.TM. (trademarks of Spectragraphics Corporation) high-performance graphic system product of Spectragraphics Corporation. The DS 1082GXP graphics system includes, in addition to a Display Controller component, a 16 inch video monitor, a keyboard, and a mouse. These additional, peripheral, components may also optionally be employed within the system of the present invention. If they are so employed then they are in lieu of or supplementary to the equivalent components which normally accompany the VAXstation.
The DS 1082GXP graphics system serves to emulate the 5080 terminal, and optionally additionally the 3270 terminal, of IBM Corporation. For the purposes of the present invention, it need only be understood that the Display Controller of the DS 1082GXP has a digital interface to the DSCC. In response to commands and information received across this interface it produces a standard Red Green Blue (RGB) video output signal which drives the presentation of displays upon a standard video monitor.
Both the DSCC and the Display Controller component of the DS 1082GXP are controlled in operation by resident firmware, or microcode, programs. No modification is required to the firmware control program of the DSCC to support its use in the system of the present invention. A modification and addition to the firmware control program of the Display Controller, as well as a modification to the hardware itself, will be seen to be required to support use of the Display Controller within the system of the present invention.
All of the previously identified hardware and software components are readily available in the commercial market circa 1988. Additionally, suitable substitutionary components from other manufacturers exist.